To evaluate vascular abnormalities at superficial (SCP) and deep (DCP) capillary plexuses and choriocapillaris (CC) in patients with Best vitelliform macular dystrophy (BVMD) by means of optical coherence tomography angiography (OCT-A). Cross-sectional case series. Sixty-six eyes of 33 patients with BVMD (16 male) and 33 controls were consecutively enrolled. Patients were subdivided into classic stages and underwent best-corrected visual acuity (BCVA), fundus autofluorescence and spectral domain-optical coherence tomography, and 4.5 × 4.5-mm swept-source OCT-A. Choroidal neovascularization (CNV) and capillary dilations were qualitatively assessed by 2 masked ophthalmologists. Each OCT-A slab was imported into ImageJ 1.50 and digitally binarized for quantitative analyses. Foveal avascular zone (FAZ) area was measured manually; vessel density was then quantified after the exclusion of the FAZ pixels. Eyes classified as stages 3 and 4 were evaluated together. Nineteen eyes (28.8%) revealed capillary dilations at DCP, 15 of which were in stages 1 and 2. Interestingly, CNV was detected in 24 eyes (36.4%). Quantitative analysis disclosed that stages 3-4 and 5 carry significant impairment at both SCP (P < .0001 and P = .02, respectively) and DCP (P < .0001 and P = .0004, respectively) compared to controls. FAZ area was enlarged at the DCP (P = .001). Only DCP vessel density significantly correlated with the stage and BCVA. Patients with BVMD show significant vascular impairment at both superficial and deep retinal plexuses, correlating with functional outcomes. These findings, especially at DCP, may improve our understanding about the pathogenesis, and may help in predicting BVMD treatment efficacy.